“ If the statutory rates permit a reasonable return, they are controlling; if they prevent it, they are invalid. But of their obligatory character the company is not the judge. And yet it must choose whether it will give effect to them or no, and then must abide the result of its action. If they be so unreasonably low as to be invalid, it cannot give effect to them without sustaining a serious and irreparable loss ”

“ And it also is to be observed that the act of 1905 and other laws of the state, as construed by the state court, afford the company no opportunity for securing a judicial determination of the validity of these rates otherwise than as it may do so in a defensive way when charged, in a case like this or in some criminal prosecution, with failing to give effect to them.
Being a common carrier, the company is not at liberty to accept or decline shipments of oil. It must receive and carry them when offered, and must be ready to name to shippers the rates at which that service will be rendered. ”

“ On the other hand, the interests of shippers and consumers of oil must be considered no less than those of the carrier. Experience teaches that to secure adherence to rates, even when lawfully prescribed, it is essential that deviations from them be discouraged by adequate liabilities and penalties.
It is in the light of these considerations that the validity of the provision imposing a liability for liquidated damages in the sum of $500 for every charge in excess of the legislative rates must be tested. ”